Blue barred parrot fish (<i>Scarus ghobban</i> Forsskal, 1775) culture in sea cages at Rameshwaram Island, Southeast coast of India

Abstract

Two square HDPE cages of 2 x 2 x 2.5 m (10 m³) size were deployed at 6 m depth in the sea at a distance of 600 m from the shore at Olaikuda fishing village. Live parrot fishes of <450 g procured from the trap fishers were sorted out into two size groups viz. 200-245 g (<img src='http://www.niscair.res.in/jinfo/xbar.gif' border=0> 214.00 ± 16.63 g) and 375-450 g (<img src='http://www.niscair.res.in/jinfo/xbar.gif' border=0> 425.00 ± 20.64 g) and stocked @ 8.5 kg/m³ separately in these cages. Low value shrimp head waste was fed @ 8-10% of total biomass stocked. The fishes were reared for two months and the culture was terminated due to severe blooming of the blue green alga, <i>Lyngbya</i> sp. Average weight gain during this 2 month culture varied between 44 g (GR 0.73 g/day) in the smaller group (200-245 g) and 98 g (GR 1.61 g/day) in the bigger group (375-450 g). A second culture trial was conducted with wild caught young fishes of approx. 100 to 140 g size and stocked them in a 9 m dia circular cage of 320 m³ cultivable volume. Culture was conducted for 130 days with pellet feed and a survival rate of 95% with the growth rate of 0.61 g/day (total average weight gain of 79.0 g).